AVS 45th International Symposium
    Electronic Materials and Processing Division Wednesday Sessions
       Session EM1-WeA

Paper EM1-WeA10
Growth and Analyses of Silicon Nitride Thin Films on Si(111) and Si(100)

Wednesday, November 4, 1998, 5:00 pm, Room 314/315

Session: Si Surface Chemistry
Presenter: X.-S. Wang, Hong Kong University of Science & Technology, China
Authors: X.-S. Wang, Hong Kong University of Science & Technology, China
N. Cue, Hong Kong University of Science & Technology, China
Correspondent: Click to Email
Silicon nitride is attractive for applications as dielectric and wide bandgap semiconductor materials. Using LEED, SPM, AES and XPS, we have analyzed geometric, thermodynamic and electronic properties of silicon nitride thin films grown on Si(111) and Si(100) substrates. The nitride films are prepared in two ways: (a) nitridation of Si substrates, i.e., by exposing clean Si samples to NH@sub 3@ or NO of various dosage and at substrate temperatures about 1150 K; (b) Si deposition under a flux of NH@sub 3@ or NO. In the second method, the substrate temperature can be kept significantly lower than 1150 K. On Si(111), the nitride thin films show a clear 8/3x8/3 superstructure. On nitrided Si(100), LEED shows a weak 1x2 + 2x1 pattern sometimes. Analysis of lattice structure of Si@sub 3@N@sub 4@ indicates that crystalline Si@sub 3@N@sub 4@ film epitaxy on Si(111) is feasible, while on Si(100) this is much more difficult. The nitride films show a remarkable thermal stability in comparison with silicon oxide films. Desorption of oxide films starts at about 1075 K, whereas the nitride films remain stable at a substrate temperature as high as 1350 K. Furthermore, surface crystalline order of the nitride films is preserved after air exposure and even after going through system baking. The implication of these results on application of nitride, oxide and oxynitride thin films in microelectronics will be discussed.